The Benefits of Using Multiple Subwoofers

A good sound system requires a good subwoofer with an optimized bass response. It doesn't matter how high-end or expensive your speakers are: Bass that sounds boomy or bloated can ruin the listening experience by drowning out higher frequencies or muddying the low end. But a tight, well-defined, evenly distributed bass can vastly enhance the listening experience—be it for a home theater, stereo, or desktop speaker system.

For audio systems that are meant to cover a large area or multiple rooms, several different subwoofers can help maintain low-end clarity while still delivering all the punch you could ask for.

Bass quality is largely determined by two factors: subwoofer placement and listener position. In a typical home environment, the bass may sound overblown in some locations yet lean in others. It all depends on where the subwoofer is placed and where you are in relation to it.

"Room resonance" refers to areas in a room where some of the subwoofer's sound waves build up, making the bass louder than it should be. Room resonances can also create areas where sound waves cancel each other out, making the bass sound weak. You can avoid or minimize these resonant "peaks and dips" by experimenting with the location of the subwoofer.

There is another factor that can influence your system's low-end response, and that's the number of subwoofers you employ. While one can usually handle enough bass for an average sized room, additional subwoofers can reduce room resonance and improve the overall quality of bass throughout the room. The thing to understand is that it's not about adding more bass; it's about distributing it more evenly throughout the room.

Two, three, or even four properly positioned subwoofers can effectively cancel some, if not all room resonances. Not only will it improve the overall bass performance, it will also expand the field of ideal listening spaces in the room. Think of multiple subwoofers like central air that can affect all areas of the home, whereas a single subwoofer is like a standing floor fan with limited reach.

A typical set-up utilizes two subwoofers positioned at opposite corners of the room. This is a sensible way to cover a space with an even but energetic low-end response. There are also subwoofer systems that include four separate subwoofers powered by one amplifier. While four subwoofers may seem like overkill, having a pair is manageable and will provide much better bass than a single subwoofer on its own.

Subwoofers vary drastically in price, from several hundred to several thousands dollars. Be sure to understand the difference between passive and powered subwoofers before making a purchase. The improvement in bass response with multiple subwoofers is so apparent that many advocate purchasing multiple smaller subs in lieu of one big one. The performance of four generally beats two, and two is always better than one.

If you're using two subwoofers, try experimenting with placement as follows:

• At opposite corners of the room.
• In the middle of the front and rear walls.
• In the middle of each side wall.

Using a similar strategy, try placing four subwoofers as follows:

• One in each corner of the room.
• One in the middle of each wall: front, rear, left, and right.

• Leave sufficient space between the subwoofer and walls.
• Remember to properly connect the subwoofer to a receiver or amplifier.
• The best-looking placement for the subwoofer isn't always the best-performing placement.
• Don't forget to adjust the frequencies on the stereo audio equalizer at the very end.
• Correct subwoofer hum/buzz when you hear it.